Power pump operated single line hydraulic system



Dec. Il, 1945. J. w. KELLY v 2,390,76

POWER PUMP OPERATED SINGLE LINE HYDRAULIC SYSTEMl Filed May 8, 1944 Patented Dec. A11, 1945 POWER rUMPoPEnA'rED lSINGLE LINE HYDRAULIC SYSTEM John William Kelly, La Canada, Calif., assigner to Adel Precision Products Corp., a corporation of California Application May 8, 1944, Serial No. 534,638

Claims.

This invention relates to hydraulic systems for operating aircraft bomb doors, landing gear. wing flaps and the like, as well as other mechanisms or devices apart from aircraft.

An object of the invention .is to provide a highly elcient, single line power pump-operated Cil hydraulic system for the purposes described in which a single uid line in one instance conducts operating iiuid to a Selective control valve for a reversible hydraulic motor or jack and in another instance returns fluid to the main reservoir so that one of the two fluid lines heretofore required 'in power pump-operated hydraulic systems between the pump and the valve, together with the plumbing, ttings and line supports therefor, are eliminated, and in consequence the costs of production, installation and upkeep, and the weight of my improved system are appreciebly reduced asis also the space required for in-l stallation thereof.

Another object of my invention is to provide a hydraulic system wherein the advantages andl objects thereof and the improvements contributed hereby are achieved by reason of the particular construction, arrangement and interrelation as herein set forth of a main reservoir, a pump connected thereto, a hydraulic motor, a' control valve for the motor, a sub-reservoir connected lto the control valve to receive fluid returned from the motor and having means to lplace the iluid therein under pressure, a single fluid line between the pump and the control valve serving as a combined pressure and return line, a valve interposed in said line Ifor aording the communication of theline with the pump or the main reservoir, and a valve operating means com mon to and for simultaneously actuating andy controlling said valves to direct 'in one instance the pressure ilud to the motor through said line while conducting return fluid into the sub-reservoir and in the other instance to shut oi flow of uid to the motor and direct the return iluid from said sub-reservoir through said line to the main reservoir. i i

Another .object of my invention is to provide a hydraulic system such as-described in which two control valves connected bya single uid line are operated by means of a novel electrical mechanism ,of simple and inexpensive construction and arrangement including atwo way circuit closer' or switch which may be conveniently located in the cockpit of an aircraft and readily operated to selectively operate the system to drive the hydraulic motor in either direction, the use of the electrical means and the single line notv only making possible the location of the hydraulic control valve close to the motor so as to provide for use of comparatively short iluid lines and reduce the cost and weight of the system, but also providing for conservation of space,

quicker .response of the system and a reduction of pressure drop as well as reduction of the vulner ability of the system where installed in military aircraft subject to attack and consequent battle damage.

With the foregoing objects in view together with Such'other objects and advantages as may subsequently appear, the invention resides in the parts and in the combination, construction and arrangement of parts hereinafter described and claimed, and the invention yis carried into eiect as illustrated lby way of example in the accompanying drawing in which:

'Fig 1 is a schematic view of a. hydraulic sys- .tem embodying my invention, showing the apparatus as when the system is operated to move the motor in one direction:

`Fig. 2 is a similar schematic view of the system when in a neutral or normal condition in whichfthe single line operates to return fluid to the main reservoir rather than to direct pressure fluid to the main control valve as shown in Fig. 1.

Referring more specically to the drawing it will be apparent that my improved system which in the present instance is particularly designed for use in aircraft, includes a main reservoir A, a power driven pump B connected thereto, a three way valve C directly connected to the pump and main reservoir in proximity thereto, a reversible hydraulic motor such as the jack D adapted to be connected to the control or device (not shown) to be operated by the system, a four-way main control valve E connected to the jack D inproximity thereto and operable to extend or retract the piston F of the jack, a spring loaded or otherwise pressurized sub-reservoir G directly con- In accordance with my invention a'iluid line 3 leads from the motor-driven or power-operated pump B to the inlet port 4 in the body 5 of the -fluid from the pump holds the valve 8 seated and shuts of iiow through the passage 6, port 1 and single line H. At this time, as is customary in hydraulic systems, the uid is passed back to the reservoir A through a short return line I I leading from line 3 and controlled by an unloading-valve i2 set to open only at a pressure above the normal working pressure of the fluid in a manner well known in the art. 4

In the three way valve C is another poppet valve i3 controlling a return port I2 opening at one end in the passage 6 at a point between valve seat I and port 1, and at its other end into a cam shaft bore Id. so that when valve 8 is unseated, valve I3 will be seated and when valve I3 is unseated, valve 3 will be seated. A short return line l leads from the cam shaft bore It' to the main reservoir A. In this connection it should be noted that the fluid lines between the pump and the main reser- L voir and between the pump and the three way valve as well as the return lines tothe reservoir from line 3 and port Hl respectively are very short and that actually the pump, the reservoir and the three way valve may be arranged in direct or substantially direct connection with one another as acompact unit for location at the power plant of an aircraft with the pump driven thereby. v Y.

The control valve 'E has its body I6 provided with a combined inlet and outlet port I1 to which the single line H is connected, and which opens into a chamber I8. Cylinder ports i9 and 20 open into the-chamber i8 at their inner ends and extend to an outer surface of the body where they y are connected to cylinder lines 2| and 22 leading to opposite ends of the cylinder 23 of the jack D. Return ports 23 and 25 afford communication of the cylinder port I9 and 2D with a cam shaft bore 25 in the body I6 which bore is provided with a port 21 to which as here shown for clarity of illustration a short conduit 28 is connected to afford communication between port 21 and the sub-reservoirfG. A

.A discharge port 23 in the body I6 of valve E extends between the cam shaft bore 26 and the chamber I8 so that fluid may be discharged from the sub-reservoir G through ports 29 and I1, intoV the single line H.

The cylinder ports. I9 and 20 are controlled by normally seated valve members lI9' and 20' held seated by pressure of iiuid in the chamber I8. The return ports 2t and 25 are controlled by normally seated valve members 24 and 25'. The discharge port 29 is controlled by a normally unseated valve member 2,9. which is vseated when either one of the valves I9' or 20 is unseated or in other words when operating uid is being directed to the jack Dl A cam shaft 33 is mounted in the bore 26 and 4 is constructed and arranged so that when turnedV in one direction from a normal position inwhich all of the valve members in valve E except the valve 29' are seated, the valves 20 and 24' will be unseated, and the valve 29' will be seated, while the valves I9' and 25' remain seated as shown in The cam shaft 9 is arranged Fig. 2'. 0n turning the shaft 30 in the opposite direction from its neutral position the valves I9 and 25' will be unseated .while valve 29 will be seated'and valves 20 and 24 will remain seated.

On return from an operative position toits neutral or normal position the cam shaft 30 will allow all valves to. seat except valve 29 which is then unseated and so held as seen in Fig. 2. As here shown the sub-'reservoir G is provided with a spring loaded false bottom or piston 3l which will be moved against the tension of the spring to increase the capacity thereof to accommodate the fluid returned from the jack D throughvalve E thereby storing upsaid return uid under pressure.

The valve operating means J which is common to the valves C and E is so constructed and arranged that it is operable to move the cam shaft 30 of .valve E in either direction from the neutral positionof the shaft which neutral position (see Fig. 2) is sustained by a force derived in the said valve operating means. The relation of the operating means J to the valve C is such that said v means also normally holds the cam shaft 9 therebranched to connect to each of the solenoids 32 of in position to seat the Valve 8 and unseat the valve I3 as shown in Fig. 2, but on each operation of cam shaft 30 to operate valve Eto cause pressure fluid to ow to the jack D, the cam shaft 9 will be turned to reverse the position of valves 8 and I3 so th'at Valve 8 opens the single line H to the pum-p While valve I3 seats and shuts od communication of passage 3 and line H to the main reservoir A.

As here shown the valve operating means J is Y electrically operated and includes axially opposed solenoids 32 and 33 having a common rack bar armature34 normally held in a centered position by springs 35 and 36. This rack armature mesheswith a pinion 31 on the cam shaft 30.

In association with the valve C is a solenoid 38 having a rack bar armature 38' normally extended .by a spring 39 and meshed with a pinion 30. The spring 39 exterts a force for holding the valve C in normal setting as shown in Fig. 2 while springs 35 and 36 likewise operate to hold the valve E in its normal condition or setting also shown in Fig. 2.

The electrical circuit for the solenoids is cohtrolled by the normally open two way circuit closer or switch K and including a conductor 3l leading from one side of a battery d2 or other source to the movable contact member d3 of the switch K, conductors M and i5 leading from the contact points M' and 45 of said switch to the solenoids 32 and 33 respectively, a conductor Q6 and 33 and leading therefrom to solenoid 38; and a conductor M leading from.- solenoid 38 to the other side of the battery 62.

Operation Normallythe valves C and E are in the set position shown in Fig. 2 due to the action of the springs 35, 36 and 39, the Valve members 8 and I3 of valve C being respectively seated and unseated, while all valve members of valve E are seated except valve 29. At this time th'e system is llled with fluid except the sub-reservoir G, the spring loadezd piston 3| which is extended asv shown in Fig.

Assuming that piston F of jack D is in the position shown in 'full line in Fig. 1 and it is desired to move it to the left into the dotted position also shown in Fig. 1, or to a position short' of the dotted position, the operator moves the switch member 43 to contact the vcontact member 44' as shown in Fig, 1 whereupon the current from battery 42 flows through conductor 4I, member 43, contact 44', conductor 45, solenoid 32,4 conductor 46, solenoid 38 and conductor 41 back to the battery 42, thereby energizing solenoids 32 and 38. Solenoid 38 retracts the rack bar armature 38 into position shown in Fig. l thereby turning the cam shaft 9 so as to unseat valve 8 and seat valve I3. At the same time solenoid 32 retracts the rack bar armature 34 so that the cam shaft 30 is turned to op'en valves 20 and 24' land close valve 29' as shown in Fig..1, the other valves I9' and 25 yremaining closed. Fluid under pressure now flows from the pump Bthrough line 3, port 4 of valve C, past open valve 8, passage 6 in valve body 5,' port 1, fluid line H, port I'I.in body I6 of valve E, ch'amber I8, past open valve 2D', thence through cylinder port 20 and line 22 to right end of cylinder 23 of jack D thereby moving piston F to the left. Fluid forced out of the left end of the cylinder 23 passes through the cylinder line r 2l into return port 24 past open valve 24' therein, into the cam shaft bore 26 thence through Iport 21 and line 28 into the sub-reservoir G. The fluid thus discharged into the sub-reservoir forces the spring loaded piston 13| toward the rbottom proper of the reservoir thusincreasing the reservoircapacity sufficiently to receive the fluid displaced from cylinder 33 and thereby placing the fluid therein under pressure.

When the -piston F has been moved a desired I 'extent in the manner hereinbefore stated, the operator manipulates the switch K to open the circuits for all the solenoids whereupon the springs 35 and 36 move the armature 34 so as to operate the camf shaft 30. to restore the valve E to normal condition shown in Fig. 2 wherein all valves are seated except valve 29' which is then held open.

At the same time that valve E is restored to neutral position, valve C is likewise operated by means of the spring 39 so that the valve member 8 is closed to shut oil the supply of pressure fluid to vline H, while return valve I3 is unseated a shown in Fig. 2.

Immediately upon closing of valve 24, the port 24 is closed and the valve 29 is opened as aforesaid, thus allowing the fluid stored under pressure' in sub-reservoir G to be forced by action of the spring loaded piston^3| throughout the line 28, port 21, cam shaft bore 26, discharge port 29 past open valve 29 into chamber I8, thence out through port Il and single line H, port 1 in valve C; passageG, past then 4open valve I3 and through port I4 and line I5 to the reservoir A, whereby in this mstance the single line H acts as a return line. The spring loaded piston .3| in subreservoir G assumes its extended position shown in Fig. 2 when the fluid therein is discharged as aforesaid to the main reservoir and theA system is ready for another operation. l

It is now apparent that when it is desired to move the jack piston F to the right, say from the position shown in full or dotted lines in Fig. 1, the

operator moves the switch member 42 into contact with contact point 4,5' thereby simultaneously energizing solenoids 33 and 38 so that valve member 8 in valve C will be opened-and valve members I3 thereof closed, while valve members I8' and 2-5' of valve E are opened and valve members 20', 24 and 28' are closed. This causes the pressure fluid from the-pump tol pass through valve C and line H into chamber I8 of valve E.

When solenoid 38 is energized solenoid 33 is alsol energized and moves armature 34 so that cam shaft 30 is turned to open valves I9' and 25' and close valve 2,9', the other valves 20' and 24 remaining closed. Fluid will now flow past open valve I9 into cylinder line 2| to the left end of cylinder 23 thus moving the piston F to the right. Fluid discharged from the right end of the cylinder is now returned through line 22 past open valve 2-5 into cam shaft bore 26 thence through port 21 and line 28 into sub-reservoir G in which piston 3l is moved inward to accommodate the displaced fluid as Ahereinbet'ore explained. The fluid thus stored in said sub-reservoir will be discharged through valveE, line H and valve C to the main reservoir when the valves'C and E are restored to normal condition u pon the opening of circuits for solenoids 33 and 38 through appropriate manipulation of switch K.

I While I have shown and described a specific embodiment of my invention I do not limit myself to the exact details of construction set forth.

I claim: l

1. In a hydraulic system, a main reservoir, a power operated pump operatively associated with said reservoir, a hydraulic reversible motor, a main control valve associated with saidmotor for directing pressure fluid formoving the motor in either direction and forvshutting off the flow between the valve and the motor, a sub reservoir connected to said valve for reception of fluid returned through the valve from said motor, means in the sub reservoir yielding upon introduction of 4such return-fluid thereto and placing such fluid under pressure sufllcient to expel it therefrom when 'said valve is actuated to shut off flow of fluid between the valve and the motor, a single fluid line for directing fluid from. the pump to the control valve and for returning fluid to the main reservoir, a second valve for controlling said single line and having a connection with said main reservoir and being operable for selectively controlling the communication of said single line with the pump and said main reservoir, and

either direction also operates the maincontrol valve to open the sub-reservoir to communication with saidmotor to-receive return fluidv therefrom and simultaneously actuates the second valve to open the single line to communication with the pump and close it to communication with said main reservoir.

2. In a hydraulic system, a mam reservoir, a

power operated pump operatively associated with said reservoir, a hydraulic reversible motor, a main control valve associated with said motor for directing pressure fluid for moving the motor in either direction and for shutting on the flow betweenvthe valve and the motor,r a sub reservoir connected to said valve for'reception of fluid returned through the valve from said motor, means in the sub reservoir' yielding upon introduction of such return fluid thereto and placing such fluid under pressure' sufiicient to expel it therefrom when said valve is actuated to shut off flow of fluid between the valve and the motor, a single-fluid line for directing fluid from the pump to the control valve and for returning uid to the main reservoir, a second valve for controlling said single line and having a connection with said main reservoir and being operable for selectively controlling the communication of said single line with the pump and said main reservoir, and operating means common to said valves and normally maintaining the second valve in position to close the single line to the pump and open it to communication with said reservoir while alsov normally maintaining said control valve in position to shut off communication of the single line with said motor but open said single line to communication with said sub-reservoir, and which when operated to actuate the main control valve to direct fluid .for operating the motor in eitherdirection also operates the main control valve to open the sub-reservoir to communication with said motor to receive return lluid therefrom and simultaneously actuates the second valve to open the single line to communication with the pump and close it to communication with said main reservoir, said valve operating means including electrically responsive valve actuating mechanisms, electrical circuits therefor, spring means associated with said devices for maintaining said valves in their aforesaid normal positions and returning them to such positions upon deenergization of said devices, and a circuit closer for controlling said circuits.

3. In a hydraulic system, a main reservoir, a pump connected with said reservoir, a hydraulic motor, a control valve for directing fluid under pressure to and for returning fluid from said motor and for shutting off i'low of iiuid between it and the motor, a sub-reservoir connected with said valve to receive'return fluid from said motor, means yielding incident to the, introduction of return fluid into said sub-reservoir and placing the uid under pressure sufficient to expel itthrough said valve when the latter is operated to shut oi the flow of fluid between said valvev and the motor, a single uid line for directing pressure fluid from the pump to the control valve in one operation of the system and for discharging return iiuid from .the sub-reservoir in another operation of the system, another valve for l controlling said single line having a connection with said main reservoir and operable for selectively affording communication of said single line withvsaid pump and said main reservoir, and valve operating means common to said valves, normally holding the second named valve in position to shut oi communication of the pump with said single line and establish communication of saidpline with said main reservoir while at the same time normally maintaining said control valve in position to shut oi ow`of fluid between the control valve and the motor and establish communication between the sub-reservoir and the single line, and which when actuated to operate said control valve to direct fluid under' pressure to the motor, causes the control valve to shut off communication of the single line with the sub-reservoir and establish communication between the motor and the sub-reservoir for conducting return'fluid to the latter and at the same time operates the second named valve to open said line to the pump and close it to the main reservoir; said operating means when operated to actuate the control valve to shut ofi` 'flow of uid between the motor and the control valve causing said valves to return to normal position whereby .the uid is expelled from the sub-reservoirl through said single line into said main reservoir.

4. In a hydraulic system a main reservoir, a pump, a reversible hydraulic motor, a selective control valve for reversing the flow of uid to said motor, a fluid line between the pump and said control valve, a. valve for controlling said line, having a flow connection with said reservoir', a sub-reservoir connected with said selective control valve to receive uid returned from the motor through said selective control valve; means for placing return :fluid in said sub-reservoir under pressure, said selective control valve including valve members operable to direct fluid for operating the motor in either direction and for conveying return ud to said sub-reservoir while shuttingvol communication of said line with said sub-reservoir and also operable for shutting oi ow of uid between it and the motor while establishing communication between said sub-reservoir and said line; the second named valve including valve members operable to shut off now from the pump to said line while opening said line t0 the main reservoir and vice versa; and operating means common to said valves normally holding the valve members of both valves in position such that the second named valve shuts oit flow from the pump to said line and opens vsaidline to communication with said main reservoir, while the control valve opens the line to communication with the sub-reservoir and shuts oi ow between the control valve and Athe motor; and means for operating said valve to the control valve and serving as a combined.

pressure and return line, a valve in said line having a flow connection to said main reservoir and y operable in one instance to establish communication between said pump and said line and shut ofi communication between said line and said main reservoir and operable in another instance to open said line to the reservoir and close said the motor, means associated with the sub-reservoir for placing the uid therein under pressure sufficient to expel it through the control valve and said line and second named valve to said main reservoir incident to coordinated operation of the said valves, said control valve having valve members operable in one instance to vsimultaneously communicate said line with the motor and communicate said motor to the sub-reservoir, and operablein another instance to shut off' the iiow of uid to and from the motor and communicate said sub-reservoir with said line, and means for electing a coordinatedoperation of said valves to operate the system as aforesaid.

6. In a hydraulic system, reversible motor, a control valve selectively operable for directing fluid to operate the motor in either direction, a main reservoir, a pump connected with the reservoir, a. single uid line leading from the pump `to the control valve and serving as a combined pressure and return line, a valve in said line hav- .ing a now connection to said main reservoir and operable 1n one instance to establish communication between said pump and said line and shutv ously communicate said line with the motor and communicate said motor to the sub-reservoir,

and operable in another instance to shut oir the flow of nuid to and from the motor and communicate said sub-reservoir with said line, and means for effecting a coordinated operation of said valves to operate the system as aforesaid, in-

cluding electrically responsive mechanism for f each valve, electrical circuits for said mechanisms providing for simultaneous operation thereof, and a switch means for controlling said circuits. l

7. In a hydraulic system, a reversible motor, a control valve selectively operable for directing fluid to operate the motor in either direction, a main reservoir, a pump connected with the reservoir, a single fluid line leading from the pump lto the control valve and serving as a combined pressure and return line, a valve in said line having a flow connection to said main reservoir and operable in one instance to establish communication between said pump and said line and shut ofi communication between said line and said main reservoir and operable in another instance to open said line lto the reservoir and close said line to the pump, a. sub-reservoir connected to said control valve to receive fluid returned from the motor, means associated with the sub-reservoir for placing the iluid therein under pressure suicient to expel itthrough the control valve and said line and second named valve to said main reservoir incident to coordinated operation of the said valves, said control valve having valve members operable in one instance to simultaneously communicate said line with the motor and communicate said motor to the 'sub-reservoir, and operable in another instance to shut oi the flow of uid to and from the motor and communicate said sub-reservoir with, said line, and means for effecting a coordinated operation of said valves to -operate the system as aforesaid, including a pair of solenoids for operating the control valve, a solenoid for operating the second named valve, electrical circuits aiiording the selective operation of the vsolenoids of said pair simultaneously with the operation of the solenoid for said second named valve, and switch means for controllingsaid circuits.

said line to the pump, a sub-reservoir connected to said controlvalve to receive fluid returned.

from the motor, means associated with the subreservoir for placing the nuid therein under pressure suiiicient to expel it through the control valve and said line and second named valve to said main reservoir incident to coordinated operation oi' the said valves, said control valve having valve members operable in one instance to simultaneously communicate said line'witn the motor and communicate said motor to the sub-reservoir,

and operable in another instance to shut oi the iiow of nuid to and trom the motor and communicate said sub-reservoir with said line, and mea-ns forv effecting a coordinated operation of said valves to operate the system as aioresaid,- including a pair of solenoids for operating the control valve, a solenoid for operating the second named `valve, electrical circuits aii'ording the` selective operation of the solenoids of said pair simultaneously with the operation of .the solenoid for said second named valve, switch means for controlling said circuits, and spring means operating through said valve operating means for normally holding said valves in position such that the control valve shuts oi iiow to and from 'the motor and affords communication -between said sub-reservoir and said line. and/ the second named valvevis likewise held in position to shut off said line to the pump and open said line to the main reservoir. 4

9. In a hydraulic system, a reversible motor, a control valve selectively operable for directing fluid to operate the motor in either direction, a

main reservoir, a pump connected with the reservoir, a single iluid line leading from the pump `to the control valve and serving as a combined pressure and return line, a valve in said line j having `a now connection to said main reservoir and operable in, one instance to establish communication between said pump and saidline and I shut off communication between said line and vsaid main reservoir and operable in another inf stance to open said line to the reservoir and close said line to the pump, a sub-reservoir connected to said control valve to receive uid returned from the motor, means associated with the sub-reservoir for placing the iluidtherein under pressure sumcient to expel it through theV control valve and said line and second named valve to said main reservoir incident to coordinated operation of the said valves, said control valve having .valve members operable in one in-` stance to simultaneously communicate said line with the motor and communicate said motor .to the sub-reservoir, and operable in another instance tovshut oi 'the ow of iluid to and from 8. In a hydraulic system, a reversible motor, a

and operable in one instanceto establish communication between said pump and said line and shut on communication between said line and Said main reservoir and operable in another instance to open said line to the reservoir and close the motor and communicate said sub-reservoir lwith said line, and means for effecting a coordinated operation of said valves to operate the system as aforesaid, including a pair of solenoids for operating the control valve, a -solenold for operating the second named valve, electrical circuits affording the selective operation of the solenoids of said pair simultaneously with the operation of the solenoidfor said second named valve, a normally open switch selectively operable to closethe circuits for the solenoids of said pair and simultaneously close the circuit for the 70.'

solenoid for the second valve, and spring means operating upon the opening of said switch to simultaneously actuate said valves to shut oil flowfrom the pump and open the single line for conducting uid from said sub-reservoir to v said main reservoir,

10. In a hydraulic system, a main reservoir, a ump having its intake connected to said main r servoir, a three-way valve at the. discharge side of said pump and having communication with said reservoir, an actuating means for said valve operable to hold it normally open'to said reservoir and closed against the discharge of said pump, a reversible hydraulic motor, a sub-reservoir, a. flow reversing valve operably connected to said hydraulic motor and said sub-reservoir, a single uid conduitl extending between said valves, means for simultaneously operating said valves, said means being constructed and arranged to selectively shift said now reversing valve from a normally-occupied neutral position and to open said three-way valve to said pump discharge and to close it to said reservoir, thereby effecting movement of said hydraulic motor, and means associated with said flow reversing valve operable to permit 'iluid discharged from said motor to be stored in said sub-reservoir under pressure, said flow reversing valve including means operable automatically to effect the return of uid from said sub-reservoir through said single fluid conduit to said main reservoir during periods when said ilo/W reversing valve is in neutral position.

JOHN WILLIAM KELLY. 

